Load sensing engine governor



Aug. 10, 1954 A. H. BLOCK 2,685,871

LOAD SENSING ENGINE GOVERNOR Filed Jan. 23, 1951 A E AUTOMATIC MANUAL CONTROL INVENTOR. ARNOLD H BLOC K F) Trek/v5 Y Patented Aug. 10, 1954 LOAD SENSING ENGINE GOVERNOR Arnold H. Block, Hackensack, N. J., assignor to Bendix Aviation Corporation, Teterboro, N. J., a corporation of Delaware Application January 23, 1951, Serial No. 207,399

16 Claims.

The present application relates to a load sensing engine governor and more particularly to a novel governor for regulating the speed of an engine for driving electrical, mechanical or hydraulic equipment.

An object of the invention is to provide a load sensitive engine governor including means to schedule engine speed with applied load and means to prevent engine stall with large step changes in loads.

Another object of the invention is to provide a novel governor to automatically regulate the' engine speed at some continuous duty rating which is a function of the load applied to the engine and in which the scheduled speed shall be increased with applied load within its operating range, and in which the speed setting schedule shall be such that at least twenty-five per cent of the net horsepower available shall be maintained in reserve for meeting surges and loads above the continuous duty rating.

Another object of the invention is to provide a novel governor in which at low engine speed settings greater reserve power is provided to meet the power requirements for acceleration, dependent upon the maximum load step change to be imposed.

Another object of the invention is to provide such an engine speed governor in which full throttle engine operation up to maximum speed may be obtainable as required for meeting surges and loads above the continuous duty rating.

Another object of the invention is to provide means responsive to the ambient atmospheric pressure for varying the speed setting of the governor with changes in such pressure.

Another object of the invention is to provide means responsive to the ambient atmospheric pressure to increase the speed setting of thegovernor upon a decrease in the atmospheric pressure and to decrease the speed setting upon an increase in the atmospheric pressure.

Another object of the invention is to provide an engine speed governor including means responsive to an operating condition of the engine which affects the power output of the engine, and means controlled thereby to increase the speed setting of the engine in response to a change in such condition in a sense to effect an increase in the power output and to decrease the speed setting upon a change in such condition in a sense to effect a decrease in the power output.

Another object of the invention is to provide such an engine speed governor in which a novel manually operable means serves to lock the governor at a particular selected speed setting within its operating range for loads requiring a constant speed setting.

Another object of the invention is to provide a novel engine speed governor incorporating easy and adequate adjustments for setting operating limits, calibration and stability.

The above and other-objects and features of the invention will appear more fully hereinafter from a consideration of the following description taken in connection with the accompanying drawing wherein one embodiment of the invention is illustrated by way of example.

The drawing is a schematic view of the load sensing engine speed governor forming the subject matter of the present application.

Referring to the drawing, there is shown in outline an internal combustion engine I of conventional type driving through a shaft 3 suitable powered equipment not shown and through gearing 5 'a shaft 1 of a speed sensing governor indicated generally by the numeral 9.

The engine I has a suitable fuel and air intake manifold H and an exhaust manifold I2 which discharges to the atmosphere. The intake manifold ll discharges into the cylinder intakes of the engine I and leads from a carburetor M of conventional type and having an air inlet conduit l5 and a throttle valve IT. The throttle valve 2'! has the usual operating lever l9 adjustably positioned through linkage 2! by the governor 9, as hereinafter explained.

The governor 9 may be considered as made up of the following main components: A flyball speed responsive device 23 driven by shaft '1 from the engine I; a servo piston 25 slidably mounted in a chamber 26 and controlled by a pilot valve 2! and in which the servo piston 25 is connected through linkage 2| with the carburetor throttle valve ll; bellows 29 sensitive to engine intake manifold pressure and ambient atmospheric pressure and operatively connected to the intake manifold pressure in conduit H through a conduit 30; an adjustable cam speed computer mechanism 3| an operator-operative lever 33 and cam 34 for manual speed selection; a speed responsive generator 31 driven by the engine I through shaft 1; a deceleration responsive solenoid 39; and suitable links, springs, adjustable stops and dashpots as hereinafter explained.

Speed governor mechanism The flyball speed responsive device 23 is of conventional design and is arranged to adjust ably position a collar ii slidably mounted on the shaft 2 and operatively connected through a governor lever 63 pivoted at .5 and connected at ts to a valve stem ll for adjusting the servo valve 2? upon changes in the engine speed. The movements of the fiyballs 23 are restricted to the minimum required for full range operation of the pilot valve 2? by adjustable stops as and tea which limit the movement of governor lever 13.

The piston 2:, controlled by the servo valve 21 is connected through a dashpot t8 and spring is to the governor lever 63. The dashpot as includes a cylinder connected to the piston 25 through a rod 5! and a piston 52 sli'dably mounted in the cylinder 5% and connected to the spring as through a rod 53. A bleed port 54 in the piston 52 permits a restricted flow oi air therethrough into the cylinder 53 so that a relatively slow adjustment of the piston 52 in the cylinder to is affected under the biasing force of the spring 49 upon adjustment of the piston 25 in a downward direction relative to the dashpot it. Thus upon adjustment .of the piston 25 in a downward direction in response to a decrease in the speed of the engine the piston 25 acting through the dashpot 38 increases the tension applied by spring as to the governor lever 63 tending to bias the lever ed in a clockwise direction so that a follow-up action is imparted by spring $9 to the lever d3 which iollow-up action is in turn wiped out by a relatively slow adjustment of the piston 52 in the cylinder under the tension of the spring l9 which adjustment of the piston 52 tends to relieve the tension of the spring is on lever t3 in a reset action by the dashopt 58.

The limited travel of the governor lever s permitted by the stops Ml and 44A, together with the reset mechanism of the dashpot 38 and spring 55 eliminates load error or droop from the governor by making the position of the flyball speed responsive device 23 independent of the position of the throttle valve ill.

The operation or" the servo piston 25 by the pilot valve 2'! transforms very small motion of the pilot valve 2'5 into larger power strokes of the servo piston 25 to which the throttle valve i'i connected through the linkage 25.

The pilot valve El arranged to provide roportional flow of servo pressure to the servo piston so that the rate of motion or the servo piston 25 will be somewhat proportional to the magnitude of impulses of speed variation. Schematically, the servo valve 2? is shown as having tapered lands which provide a gradual change in port opening to the piston chamber as with lllO- ion of the valve 2?. Action of the pilot valve 2? is damped by a second dashpot 5i operatively connected at 58 to the valve stem 41' by a lever arm 53 pivoted at St,

Speed setting mechanism The speed setting of the fiyball speed responsive device 23 may be varied-through operation of the bellows 2?: which may be of conventional metallic type, selected so as to be adjustably positioned in accordance with changes in the intake manifold and atmospheric pressure. The schematic drawing shows a single bellows 29 with a chamber 83 and a bellows seal lid. The chamber :33 is operatively connected through a passage 55, an opening 5? in a sl-idable valve and a passage l! connected through conduit as to the intake manifold pressure in conduit H leading to the engine i.

Atmospheric pressure acts exteriorly on the bellows 2s and thus displacement of the bellows 29 will be dependent upon the difference oetween the intake manifold pressure applied to the chamber 53 and atmospheric pressure applied exteriorly to the bellows 29 so as to vary the speed-setting of the engine I with changes in atmospheric pressure as well as changes in the intake manifold pressure.

However, should it be desired that the control of the speed setting of the flyball speed responsive device 23 be independent of changes in atmospheric pressure, the bellows assembly 29 may instead incorporate an evacuated bellows mounted in a sealed chamber and subject exteriorly to the intake manifold pressure as provided in the bellows structure disclosed and claimed in U. S. Patent No. 2,358,845 granted September 26, 1944 to Howard A. Alexanderson and assigned to Bendix Aviation Corporation and which bellows structure may be arranged so that pressure absolute rather than gauge pressures may be measured.

A link '53 leads from bellows seal i l to a cam speed computer mechanism indicated generally by the numeral 3i and including an adjustable cam "55 rotatable on an axis l t and positioned through the link 13 and an arm it so as to con vert the adjusted position of the bellows 253 responsive to the prevailing atmospheric and intake mainiold pressures into a proper calibrated displacement or a speed setting spring l3 through adjustment of a cam follower lever 83 pivoted at fil. The speed setting spring i8 is connected at one end to an end 83 of the cam follower lever til and at the opposite end 85 to the governor lever 53.

The force applied by the spring l8 to the lever 53 represents the speed setting or null position of the flyball speed responsive device 23, since this force must be balanced by the flyball force in order to bring the control valve 2'? to a null position. The cam l5 is so designed that within its operating range the speed setting increases with the intake manifold pressure which in turn increases with the opening of valve It in response to an increase in the load applied to the engine i.

Moreover by properly designing the contour of the cam E5, the speed setting schedule is such that at least twenty-five per cent of the net horsepower available from the engine l is maintained in reserve to meet surges and loads above the continuous duty ratingand at low engine speed settings greater reserve power is provided to meet the power requirement for accleration.

The power output of the engine A increases with an increase in the intake manifold pressure in conduit ll. Now if the air inlet conduit 55 be pressurized to provide a constant air inlet supply pressure, the power output of the engine I will also increase with a decrease in the ambient atmospheric pressure owing to the corresponding decrease in the exhaust counter-pressure effected by such decrease in atmospheric pressure. Thus instead of the bellows 2% only measuring the absolute intake manifold pressure in the conduit H, the same is arranged, as shown in the drawing, to be responsive to the surrounding ambient atmospheric pressure as well as to the intake manifold pressure in the conduit l l and is so designed as to vary the position or" the cam '55 and the speed setting of the engine 8 in accordance with the power output'ot the engine l as rei the engine I below the selected value.

fiected by the prevailing atmospheric and intake manifold pressures. Thus, upon an increase in atmospheric pressure tending to decrease the power output of the engine I, the cam I is adjusted by the bellows 29 so as to decrease the speed setting of the engine I, while a decrease in atmospheric pressure tending to increase the power output causes the bellows 29 to adjust cam 75 to increase the speed setting of the engine I.

Similarly an increase in the intake manifold pressure affects the cam I5 so as to increase the speed setting of the engine I, while a decrease in the intake manifold pressure effects a decrease in the speed setting of the engine I. Such changes in the intake manifold pressure reflectnot only changes in the power output of the engine I, but also changes in the load applied to the engine I, since as the load applied to the engine I is increased the valve I1 is further opened to increase the intake manifold pressure at conduit II in response to a decrease in the speed of A decrease in the load applied to the engine I has an opposite effect of permitting the speed of engine I to increase causing the speed responsive device 23 to tend to close the valve I! to decrease the intake manifold pressure.

Of course, if anincrease in the atmospheric pressure effects also a corresponding increase in the intake manifold pressure or a decrease in the atmospheric pressure effects also a corresponding decrease in the intake manifold pressure, the change in the one pressure would be counter-balanced by the change in the other pressure acting upon the bellows 29.

The bellows 29 and cam 3I thus provide means for setting the required speed-load characteristics of the control in accordance with changes in the applied load and power output of the engine so as to vary the speed setting of the control in direct relation with change in the aplied load and power output of the engine.

Deceleration control to prevent engine stall Further driven by the shaft 1 of the speed responsive device 23 is the accelerometer 31 which consists of a D. C. generator whose electrical output is fed through lines 81 and 89 into a simple capacitor-resistance circuit indicated generally by the numeral 90 of conventional type or the same may be a deceleration .responsive circuit of the type disclosed in U. S. application Serial No. 561,083, filed October 30, 1944, by Joel D. Peterson and assigned to Bendix Aviation Corporation.

- The circuit 99 is of a type arranged to differentiate the speed signal from the generator 3? and give a D. C. output to lines 92 and 94 proportional to the deceleration of the engine I. The signal in the circuit 90 is further so biased that only deceleration signals greater than a certain magnitude will cause effective energization of the output lines 92 and 94.

A typical example of the deceleration responsive circuit is shown diagrammatically in the box 90 in which the output lines 8! and 89 of the D. 0. generator 31 are shown as leading into a simple capacitor-resistance circuit l20responsive to the rate of change in the current produced by the generator 31 due to changes in the driven speed thereof. The output line 87 leads from the posi- .-.tive terminal of the D. C. generator 31' while the Qof. thegenerator 31. V. H

In the circuit I20 a load resistance I 22 is connected across the lines 81 and 89. There is furthr provided a condenser having a plate I26 connected to the negative line 89 and an opposite plate I28 connected by a line I29 to a grid I30 of an electronic valve I32. Across the lines 31 and I29 is connected a second resistance MI. The electronic valve I32 is provided in the conventional manner with a heater I42 for the cathode I49 and the energizing circuit for the heater is indicated generally by the numeral I44.

The electronic valve I32 has a plate element I43 connected by the output conductor 92 to one end of an electromagnetic winding 96, the opposite end of which is connected by conductor 94 to the positive terminal of a battery or other suitable source of electrical energy indicated generally by numeral I48. The negative terminal of the source or" electrical energy I48 is connected by a conductor I5i'. to the cathode I40. The cathode I49 is also connected by a conductor I52 to the positive terminal or a battery I54 or other suitable source of electrical energy or biasing voltage while the negative terminal of the battery I54 applies through a conductor I 56, resistance MI and conductor I29 a negative bias to the grid I30 tending to retard electron flow through the electronic valve I32 and prevent effective energization of the electromagnetic winding 95, except in the event of a deceleration signal in excess of a predetermined minimum value, as hereinafter explained.

Thu upon the speed of the engine I being decelerated at a rate in excess of the critical minimum value, causing a corresponding decrease in the speed of rotation of the D. C. generator 3i and decrease in the output of the D. C. generator 31, it will be seen that the negative charge applied to the condenser plate 126 will likewise be decreased due to a decrease in the voltage drop through the load resistance 22.

Such'decrease in the electromotive force acting on the condenser plate I26 will effect a decrease in the electrostatic forces acting in the dielectric material between the condenser plates I25 and I28 so as to cause an electron flow from the condenser plate I26 through resistances I22 and MI to the'opposite condenser plate I28 to equalize the'eifect of the decrease in electromotive force acting'on the condenser plate I2t. The condenser plate I28 during such electron discharge period, or the speed decelerating period of the engine I, acquires a higher potential than the condenser plate I26 due to the fall of potential through the resistances I22 and MI.

The grid I39 connected to the condenser plate I 28 thus acquires a more positive charge. under the critical deceleration conditions so that electron flow from the cathode I46 to the plate I45 increases so a to in turn cause the effective energization of the electromagnetic winding in the output lines 92 and 94. Of course, upon the deceleration in the engine speed being corrected, the bias applied to the grid I33 becomes more negative whereupon the electron flow through the electronic valve I32 ceases to effectively energize the electromagnetic winding 96.

The output lines 92 and 94 are connected to the electromagnetic winding 96 of the solenoid 39 arranged to actuate a solenoid plunger 58 to in turn actuate through a spring I99 the lever arm 59 to adjustably position the servo valve 21 in a direction, as indicated by the arrow, to affect opening of the throttle valve I1 upon the .speed of the engine I decelerating in excessof 1 flapper valve ltfi does not opstruchjhflro ,valve it upon a momentary-deceleration f engine i to below the criticalva ue which momenthe m nimu v u -determin d it-the sett n of th circuitQil.

The mov t it e er t rnrttwu d rwt biasin fo e; f the hri e; 10. i damned? rzt dashpot ii. The dashpot =5 as,:;.proyided. a cylinder portion ,.,ligol 582- to t i connect d m the arm .53 and siidablv. monntedjnthe cylinder portion Iiil is a piston m3;,f1-xedly a rod 1G4. A-flapper valve 405.;1is

Ili d. y

limit the opening of a bleeder. port ;-gl6-. extend--..=

ing through a piston iiifi ofdashpot upon downward movement of the cylinde1; -;portion It i under the biasing force of spring Misc-that adjustment by the solenoid plu nger. 98 through spring we of the lever 5& ;in-

directionto.

actuate the servo valve-21 m asQDSez Qn effecting an opening of the throttle valve I} upon deceleration isirnparted to the lever;fiasomewhat more slowly than adjustment:of the servo valve 21- in the opposite directionto decreasewtheiopening of .the

of port 5% to the outflow of air portion It]! so that, thendamp dashpot ti on the leverandgvalveqll is .not:::

so great.

The arrangement of; the-dashpot i5l; in.the manner indicated is to provide; stability, of, control and prevent over-adjustment-oifilm-throttle tary deceleration is taken care;oi by the speed responsive deviceZE of -the, regu1at i ng;system in the normal manner.

M anual control As shown, in the drawing there. is further provided the manually operable;leverssil pivoted at it? and operably connectedatJflB-to thecam 3 which. has formed integral therewith the slide end of a rod H2 projecting .from asealing-plate 6d of the bellows 2G soas to manuallyselectthe speed setting of the engine I.

Initial movement of the 1. eV6IT,3. 3..fI Om 1JhQ range AB to B-C affects the sliding valve fifi so as to close the opening G'i.to the passage1li; and

open the valve opening toa passage, l [4. leading to a-trnosphericpressure. 1Thu initialmovement of the lever 33through.operationofyalvei69 cuts oil the intakemanijold pressure jrom jthe chamber 63 of the, bellows 3 29 and pensj the bellows chamber B3 to the atmospheric pressuref subsequent mo vernent of the lever 33 'within' the manual control range causes the c am"34 to ,act upon the bellows 28 through the. rod-H2 and thereby adjust the camlfi tomanuallyselect-the engine speed.

Thus the governor forming ,the subject matter of the present application provijdesmeans for setting the speed of, the engine automatically in accordance with theapplied load and power output of the engine and alternatelyin accord ance with the manualadjustmentorthe'lever33.

- ppemtz'on Upon the governor 9 being set forautomatic the , piston 52 of theda'shpot .tiunder the biasing -indicator--23 to be eliected through the-mechenditicn i ma o by the .servo valvecfl is then admitted-to the 'piston chamber 26 at the top of the servo piston .25 -movingvthe. piston; 25 and dashpot 58 downward-increasing the tension of springrde applied ,to the governor. lever-A3, and. positioning the ,throttle valve 2-],in an opening: direction increas- .,ing the intakemanifold pressure to the engine I and the power output ofthe engine I.

.As shown. in the, drawing .movement of. the governor lever v43 islirnitedby the .stopsAi and 44Av so thatnegligible load. error is introduced into the speed setting spring! 8.

. Now as theservo piston.2,5, moves the throttle valve ll towardsvthe open position, the piston. 52 of. the. dashpot. .ttmoves very .slowly relative. to

the. piston 25, .so. that; there visapplied to the governor lever... i3. .through..thejpiston. 52 and ..follow up. spring .49 .a biasing force.. tending to balance, the.. count eriorce 0f .the. fiyball speed responsive device 23, thusbringing the. pilot valve 21 .baclhto null andst ppingfurther adjustment .of the servo. pistonjfi. Duringthis' time, the

force of the followmp springjtt is adjusted relative to the piston r ifi sou as to wipe out the follow-up eflfectgof the spring' it and-reset the governor lever &3 so as to eliminate the load error or follow-upefiectthathasbeen introduced by the displacement. Oifthe servo pistoirzfi.

jThe previous. actiontal es place with small decreases in speed. "However; should. a large increase in the load causea deceleration of the engine l greater than that-permitted-by the setting'of the circuiti'tfl then thespeed'responsive generator-31 and solenoid 3 9 come into operation to prevent-theengine I going into astall. A signal;fromthggenerator;31auponrsuchfimessive deceleration conditions. will cause the electroma net w nd to. a tua e; e-...solen0 plu r .8 to. i crea e t t ns nottm s ri 106 applied to the lever {43, which inturnmoves the servo pilot valvefZfl. subject to the retarding effect of the dashpot ""51 to bring the' throttle valve" 5 lof the carburetor I 4 to maximum throttle to prevent theengine l fromstalling under load conditions.

In the .casegof a decrease in the load applied senses the resulting increasein engine -speed-to close the valve-l l", decreasingthe intake manifold pressureand power output ofthe engine. Such decrease in theintake manifold pressure in; turn causes a decrease in; the speed setting ofthe speed anism 3L- Thus-uponsuch-a deereasein load causing -'-the fiyballs "Of the- --speed-- responsive device 23-to move-out-ward,-collar M to move upward; and a clockwise adjustment 1 of v the downward directing ser-vo pressure to theservo tlevalve H to. in-turndecrease the intake manifold pressureapplied through the conduit SB-to the chamber '63 of the bellows 2 This, in: turn,

- causes' the bellows -.129 to collapse -moving the cam- 15 in @nGOUHtQY-QlQCkWlSB direction andthe operation,- it will te -seen that-during constant -7 cam follower lever which follows thescam=surface of the cam l to likewise move in a counterclockwise direction to decrease the tension of the spring 18 and thereby decrease the speed setting of the speed responsive device 23 upon such a decrease in load.

The rate of deceleration of the engine i is of course fixed by the setting of, the circuit St which upon the speed of the engine l tending to decrease at an excessive rate affects the solenoid 39 so as to in turn tend to limit the rate of de crease in the speed of the engine l, as heretofore explained.

The manual speed lever 33 may be adjusted within the manual control range B- so as to by-pass the automatic load speed scheduling affected through the bellows 29 and effect manual selection of any speed within its operating range independent of load.

Initial movement of the lever 33 cuts ofi the manifold pressure to the bellows 29 through operation of the valve 69 and opens the bellows 29 to atmospheric pressure; subsequent motion causes cam 34 to act upon the bellows 29 so as to displace it the proper amount for the desired manual speed schedule effected through adjustment of the cam 15.

Although only one embodiment of the inventionhas been illustrated and described, various changes in the form and relative arrangements of the parts may be made to suit requirements.

What is claimed is:

l. A speed governor for an internal combustion engine having an air intake conduit and a throttle valve for controlling the pressure in said conduit, comprising, in combination, an engine speed responsive device for regulating the throttle valve, means for changing the datum of said engine speed responsive device, operating means for said datum changing means including an engine condition responsive control means and a manually operable control means, and operator-operative means for selectively transferring from one to the other of said control means.

2. The combination defined by claim 1 in which said condition responsive means includes an ambient atmospheric pressure responsive means.

3. The combination defined by claim 1 in which said condition responsive means includes a pressure sensing device responsive to the pressure in the air intake conduit of the engine. I

4. The combination defined by claim 1 in which said condition responsive means includes a differential pressure sensing device responsive to the difierence between ambient atmospheric pressure and the pressure in the air intake conduit of the engine.

5. The combination defined by claim 1 in which said operator-operative transfer means includes a device operatively connected to said manually operable control means.

6. A load sensitive governor for an engine, comprising. an engine speed regulating means, means for changing the datum of said speed regu lating means, engine load condition responsive means, means operatively connecting said condition responsive means to said datum changing means so as to schedule engine speed in accord ance with the load applied to the engine, and

means for changing the datum of said speed responsive means, engine load condition responsive means, means operatively connecting said condition responsive means to saiddatum changing means so as to schedule engine speed in accordance with the load applied to the engine, engine deceleration responsive means, engine speed control means, means operatively connecting the speed responsive means to said speed control means, and other means operatively connecting the deceleration responsive means to said speed control means so as to prevent engine stall upon a relatively large increase in the load applied to said engine.

8. A load sensitive governor for an engine, comprising an engine speed regulating means, means for changing the datum of said speed regulating means, engine load condition responsive means, means operatively connecting said condition responsive means to said datum changing means so as to schedule engine speed in accordance with the load applied to the engine, and operator-operative means for connection to said connecting means and arranged to operate said datum changing means independently of said condition responsive means.

9. For use with an internal combustion engine having an induction conduit, an induction throttle valve and an exhaust conduit to atmosphere; a load sensitive enginespeed governor comprising an engine speed responsive regulator, means for operatively connecting said regulator to said throttle valve to vary the position of said valve and thereby change the induction pressure so as to maintain a selected engine speed upon a change in the load applied to said engine, means for changing said selected engine speed, a differential pressure responsive device sensitive to the difference between such induction pressure and the ambient atmospheric pressure, means operatively connecting said differential pressure responsive device to said speed changing means to effect a change in the selected engine speed in direct relation to such change in load so as to schedule engine speed in accordance with the load applied to the engine and to effect a change in the selected engine speed in inverse relation to a change in the ambient atmospheric pressure relative to said induction pressure, and engine deceleration responsive means operatively connected to the connecting means between the regulator and'throttle valve to open said throttle valve upon excessive deceleration of the engine so as to prevent stalling of the engine upon a relatively large increase in the load applied to said engine.

10. For use with an internal combustion engine having an induction conduit, an induction throttle valve to control the pressure in said induction conduit; a load sensing engine speed governor comprising a flyball speed responsive device sensitive to the speed of the engine, a governor member operable by said device in response to the engine speed, a speed setting spring means biasing said governor member in opposition to said device, a servo valve, means operatively connecting said governor member to said servo valve, a servo piston controlled by said servo valve for positioning the induction throttle valve, a bellows, conduit means operably connecting the induction pressure to one side of the bellows, said bellows being operatively adjusted by changes in the induction pressure, cam means for varying the speed setting of the spring means, and means operatively connecting said hellows to ass-5:871

said 'cain' means for var71'ng""the speed" setting directly :with changes in:themautidhpressure;

eluding a manually'oper'able"cam, a rodproje'ct ing from said bellowsand operative by said cam so'as to directly coiitrol'the" s'pe'ed'setti'ng cahi means independentl'y of "said" bellows? 12. The combination defined by"cla imll inf cludili'g a transfer va1ve fo'fi'fiec'l integrarwiththe manually operablecam t'o*close upon a predeter" mined movementthereof "thec'onduit' meanscon: necting'the induction ressure to theion'e' side" of said bellow-sand to op'erfsaid one side'ofthe bellows to atmospheric pressure.

131 The combination define'd'by Lcl'aix'n' 10 includin'gdeceleration i'espon's'ive rne'ans' effective" upon deceleration" ofth'en'gifief in excess "of a predetermined value; an auxiliary"membermp' eratively connecting' saiddeceleratidn responsive" meansto the means connecting said 'go'v'eino'r memberto said servo "value, auxiliary" spring" means for biasing saidauxiliai'y member in'a direction to operate saidse'rvo' valve in a direction for opening said throttle valve; and-niotor'means;

controlled by said deceleration responsive means for effecting operation of said auxiliary spring l on. .i

1e. {The-combination defined by' claim 13"ineluding means for retarding adjustment 'ofsaid auxiliary member bysaidauxiliarvspring means upon a momentarytleceleration of theengine 15 The combination defined by claim 13' which the retarding means includes a dashpot and a flapper valve means'arranged'} to retard adjustment of said auxiliaryimember by .said auxiliary spring Lme'a'ns up'on a momentary deceleration of the engine whilepermitti'n'g-a damped adjustment of the auxiliary member in 12 an opposite direction upon cessation "of "the deceleration':

16; For use with an" internal combustion "en' gine'hav'ingan" induction conduit; an induction" throttle valve to control the pressure in said in duction "conduit anclan' "exhaust conduit to atniosphere, a load sensitiveengin'e' speed 'gover nor comprising a flyball'speed responsive'device" sensitive to speed ofthe engine; a governor mem 'ber "operable by's'ai'cl 'devicein' response to the" en-' ginespe'e'd, a speed" setting spring" means biasing said governor member in opposition tosaidde vice; a servo valve, means "opera'ti'vely' connecting said governor member't'o said" servo valve, a

' servo piston "controlled" by said"'servo"valve"for positioning the" induction "throttle valve, a differential" pressure" responsivebellows; conduit" means operably connecting theindu'ction" pres sure to'one side of 'thebel1ows','the" bellows being pressure and inversely with changes *in the" am;-

" bient atmospheric'pressurerelative'to said induc tion pressure.

References Citedin thewfile of-this patent UNITED STATES PATENTS Number Name Date 2,221,201 Pope Jrjyet al. Nov. 12; 1940' 2,529313'7" Weinberger Nov. 7, 1950' 2,555,734 Catford June 5, 1951 

